This document specifies the sizing of safety valves and bursting discs for gas\/liquid two-phase flow in pressurized systems such as reactors, storage tanks, columns, heat exchangers, piping systems or transportation tanks\/containers, see Figure 2. The possible fluid states at the safety device inlet that can result in two-phase flow are given in Table 1. NOTE The pressures used in this document are absolute pressures, not gauge pressures.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 6<\/td>\n | Annex ZA(informative)Relationship between this European Standard and the essential safety requirements of Directive 2014\/68\/EU (Pressure Equipment Directive) aimed to be covered <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | Foreword <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | Introduction <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 1 \u200bScope 2 \u200bNormative references 3 \u200bTerms and definitions 3.1 \u200bGeneral <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 3.2 \u200bPressure <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 3.3 \u200bFlow rate <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 3.4 \u200bFlow area 3.5 \u200bFluid state 3.6 \u200bTemperature <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 4 \u200bSymbols and abbreviated terms and figures 4.1 \u200bSymbols <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4.2 \u200bAbbreviated terms <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 4.3 \u200bFigures <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5 \u200bApplication range of the method 5.1 \u200bGeneral 5.2 \u200bLimitations of the method for calculating the two-phase mass flux in safety devices 5.2.1 \u200bFlashing flow <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 5.2.2 \u200bCondensing flow 5.2.3 \u200bFlashing flow for multi-component liquids 5.2.4 \u200bDissolved gases <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 5.2.5 \u200bCompressibility coefficient \u03c9 5.3 \u200bLimitations of the method for calculating the mass flow rate required to be discharged 5.3.1 \u200bRate of temperature and pressure increase 5.3.2 \u200bImmiscible liquids 6 \u200bSizing steps 6.1 \u200bGeneral outline of sizing steps <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 6.2 \u200bStep 1 \u2014 Identification of the sizing case <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 6.3 \u200bStep 2 \u2014 Flow regime at the inlet of the vent line system 6.3.1 \u200bGeneral 6.3.2 \u200bPhenomenon of level swell 6.3.3 \u200bInfluence of liquid viscosity and foaming behaviour on the flow regime <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 6.3.4 \u200bPrediction of the flow regime (gas\/vapour or two-phase flow) <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 6.4 \u200bStep 3 \u2014 Calculation of the mass flow rate required to be discharged 6.4.1 \u200bGeneral 6.4.2 \u200bPressure increase caused by an excess in-flow <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 6.4.3 \u200bPressure increase due to external heating <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | 6.4.4 \u200bPressure increase due to thermal runaway reactions <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | 6.5 \u200bStep 4 \u2014 Calculation of the dischargeable mass flux through and pressure change in the vent line system 6.5.1 \u200bGeneral <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | 6.5.2 \u200b Two-phase flow discharge coefficient, Kdr,2ph <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | 6.5.3 \u200bDimensionless mass flow rate, C <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | 6.5.4 \u200bCompressibility coefficient, \u03c9 (numerical method) <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | 6.5.5 \u200bCalculation of the downstream stagnation condition 6.5.6 \u200bSlip correction for non-flashing two-phase flow <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | 6.5.7 \u200bSlip correction for two-phase flow in straight pipes 6.6 \u200bStep 5 \u2014 Ensure proper operation of safety valve vent line systems under plant conditions 6.7 \u200bSimultaneous calculation of the dischargeable mass flux and pressure change in the vent line system <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | 6.8 Summary of calculation procedure <\/td>\n<\/tr>\n | ||||||
| 54<\/td>\n | Annex A (informative) Identification of sizing scenarios <\/td>\n<\/tr>\n | ||||||
| 56<\/td>\n | Annex B (informative) Example calculation of the mass flow rate to be discharged <\/td>\n<\/tr>\n | ||||||
| 60<\/td>\n | Annex C (informative) Example of calculation of the dischargeable mass flux and pressure change through connected vent line systems <\/td>\n<\/tr>\n | ||||||
| 77<\/td>\n | Annex D (informative) Environmental factor <\/td>\n<\/tr>\n | ||||||
| 78<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Safety devices for protection against excessive pressure – Sizing of safety valves and bursting discs for gas\/liquid two-phase flow<\/b><\/p>\n |